Method and ocular implant for transmission of nerve-stimulation light

ABSTRACT

An improved prosthesis and method for stimulating vision nerves to obtain a vision sensation that is useful for the patient that has lost vision due to age-related macular degeneration (AMD) and retinitis pigmentosa (RP) and other diseases. The present invention utilizes infrared light to cause action potentials in the retinal nerves similar to those which result from rods and cones stimulated by visible light in healthy retinas. In some embodiments, the invention provides a pathway or “image pipe” for transmitting a stimulation pattern of infrared light from an external stimulator array through the eye and focusing the stimulation pattern of infrared light on the retina, especially the fovea. Some embodiments provide improved resolution down to a group of nerves, or even the individual nerve level, with sufficient energy density so as to cause a desired action potential.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a divisional of U.S. patent application Ser. No.13/204,610 filed Aug. 5, 2011, titled “Ocular Implant and Method forTransmission of Nerve-Stimulation Light” (to issue as U.S. Pat. No.8,709,078 on Apr. 29, 2014), which claims priority benefit under 35U.S.C. §119(e) of U.S. Provisional Patent Application No. 61/514,894filed Aug. 3, 2011, titled “Sight-Restoring Visual Prosthetic and MethodUsing Infrared Nerve-Stimulation Light” (Attorney Docket 5032.067PV1),both of which are incorporated herein by reference in their entirety.

This invention is related to the following prior applications andpatents:

U.S. Provisional Patent Application No. 60/715,884 filed Sep. 9, 2005,titled “Apparatus and Method for Optical Stimulation of Nerves”(Attorney Docket 5032.009PV1);U.S. patent application Ser. No. 11/257,793 filed Oct. 24, 2005, titled“Apparatus for Optical Stimulation of Nerves and Other Animal Tissue”(now U.S. Pat. No. 7,736,382 issued Jun. 15, 2010, Attorney Docket5032.009US1);U.S. Provisional Patent Application No. 60/826,538 filed Sep. 21, 2006,titled “Miniature Apparatus and Method for Optical Stimulation of Nervesand Other Animal Tissue” (Attorney Docket 5032.020PV1);U.S. patent application Ser. No. 11/536,639 filed Sep. 28, 2006, titled“Miniature Apparatus and Method for Optical Stimulation of Nerves andOther Animal Tissue” (now U.S. Pat. No. 7,988,688 issued Aug. 2, 2011,Attorney Docket 5032.020US1);U.S. patent application Ser. No. 11/536,642 filed Sep. 28, 2006, titled“Apparatus and Method for Stimulation of Nerves and Automated Control ofSurgical Instruments” (Attorney Docket 5032.023US1);U.S. Provisional Patent Application No. 60/884,619 filed Jan. 11, 2007,titled “Vestibular Implant Using Infrared Nerve Stimulation” (AttorneyDocket 5032.026PV1);U.S. patent application Ser. No. 11/971,874 filed Jan. 9, 2008, titled“Method and Vestibular Implant using Optical Stimulation of Nerves”(Attorney Docket 5032.026US1);U.S. Provisional Patent Application No. 60/964,634 filed Aug. 13, 2007,titled “VCSEL Array Stimulator Apparatus and Method for LightStimulation of Bodily Tissues” (Attorney Docket 5032.038PV1);U.S. patent application Ser. No. 12/191,301 filed Aug. 13, 2008, titled“VCSEL Array Stimulator Apparatus and Method for Light Stimulation ofBodily Tissues” (Attorney Docket 5032.038US1);U.S. Provisional Patent Application No. 61/015,665 filed Dec. 20, 2007,titled “Laser Stimulation of the Auditory System at 1.94 μm andMicrosecond Pulse Durations” (Attorney Docket 5032.041PV1);U.S. Provisional Patent Application No. 61/147,073 filed Jan. 23, 2009,titled “Optical Stimulation Using Infrared Lasers (or In Combinationwith Electrical Stimulation) of the Auditory Brainstem and/or Midbrain”(Attorney Docket 5032.046PV1);U.S. patent application Ser. No. 12/693,427 filed Jan. 25, 2010, titled“Optical Stimulation of the Brainstem and/or Midbrain, includingAuditory Areas” (Attorney Docket 5032.046US1);U.S. Provisional Patent Application No. 61/349,813 filed May 28, 2010,by Jonathon D. Wells et al., titled “Laser-Based Nerve Stimulators for,e.g., Hearing Restoration in Cochlear Prostheses” (Attorney Docket5032.063PV1);U.S. Provisional Patent Application No. 61/381,933 filed Sep. 10, 2010,by Jonathon D. Wells et al., titled “Laser-Based Nerve Stimulators for,e.g., Hearing Restoration in Cochlear Prostheses and Method” (AttorneyDocket 5032.063PV2);U.S. patent application Ser. No. 12/890,602 filed Sep. 24, 2010, byJonathon D. Wells et al., titled “Laser-Based Nerve Stimulators for,e.g., Hearing Restoration in Cochlear Prostheses and Method” (AttorneyDocket 5032.063US1);U.S. Provisional Patent Application No. 61/349,810 filed May 28, 2010,by Jonathon D. Wells et al., titled “Implantable Infrared NerveStimulation Devices for Peripheral and Cranial Nerve Interfaces”(Attorney Docket 5032.064PV1);U.S. Provisional Patent Application No. 61/386,461 filed Sep. 24, 2010,by Jonathon D. Wells et al., titled “Implantable Infrared NerveStimulation Devices for Peripheral and Cranial Nerve Interfaces”(Attorney Docket 5032.064PV2);U.S. patent application Ser. No. 13/117,121 filed May 26, 2011, byJonathon D. Wells et al., titled “Implantable Infrared Nerve StimulationDevices for Peripheral and Cranial Nerve Interfaces” (Attorney Docket5032.064US1);U.S. patent application Ser. No. 13/117,122 filed May 26, 2011, byJonathon D. Wells et al., titled “Cuff Apparatus and Method for Opticaland/or Electrical Nerve Stimulation of Peripheral Nerves” (AttorneyDocket 5032.064US2);U.S. patent application Ser. No. 13/117,125 filed May 26, 2011, byJonathon D. Wells et al., titled “Nerve-Penetrating Apparatus and Methodfor Optical and/or Electrical Nerve Stimulation of Peripheral Nerves”(Attorney Docket 5032.064US3);

U.S. patent application Ser. No. 13/117,118 filed May 26, 2011, byJonathon D. Wells et al., titled “Optical Bundle Apparatus and Methodfor Optical and/or Electrical Nerve Stimulation of Peripheral Nerves”(Attorney Docket 5032.064US4);

each of which is incorporated herein by reference in its entirety.

FIELD OF THE INVENTION

The invention relates generally to methods and apparatus for visionrestoration and optical nerve stimulation, and more particularly to amethod and apparatus for transmission of infrared optical stimulation tonerves (in contrast to the regular optical sensing rod and cone cells)in a human eye to obtain a sensation of vision.

BACKGROUND OF THE INVENTION

For many patients suffering from retinal degenerative diseases such asadvanced or age-related macular degeneration (AMD) and retinitispigmentosa (RP) there has been little hope for maintaining vision. Everyyear, 700,000 new cases of AMD in the U.S. are diagnosed and 10% ofthose patients will become legally blind. There are presently no curesfor these debilitating diseases, and, at best, current treatments onlyslow the disease progression. The overall social and economic impact ofAMD and RP is immense and the importance of treating blindness isprofound as this is a problem of significant scope and breadth. There isan unmet need to treat this ailment by developing a visual prostheticwith a large number (e.g., thousands) of stimulation channels torealistically restore sight using infrared light to stimulate theretinal nerves. Advanced macular degeneration and retinitis pigmentosaare both diseases that degrade vision in patients and eventually willlead to blindness.

Researchers have artificially stimulated various parts of the humannervous system for many years as a way to restore lost or damaged neuralfunction of various systems in the human body. Neuroprosthetic devicescircumvent non-functioning physiological structures (hair cells in theear, rods and cones in the eye) which would normally transduce anexternal stimulus (sound, light) into an action potential. Presently,there are numerous efforts underway to develop neuroprostheses torestore sight at various interventional anatomical locations: in thesubretina, the epiretina, the optic nerve and in the visual cortex.These devices apply an electric current pulse to stimulate the neuronsof the visual system which is inherently hindered by a lack of spatialselectivity. Electrical current spread leads to imprecise nervestimulation and limits the ability of the neuroprosthesis to restorefunction. The limitation of spatial selectivity is based on fundamentalphysical principles of electrical stimulation. To date, after 20 yearsof development, electrical implants are just now hoping to make the jumpto 64-channel systems from 16-channel systems. This is far less than thethousands of channels estimated to be needed for a good visionprosthetic. The technology is further limited by the fact that physicalcontact is required with tissue, which can lead to damage over time.Implantation of a complex powered device in very close proximity tosensitive neural tissue forms a significant drawback to this approach,making it impossible to update the technology without further riskysurgeries.

There have been rudimentary attempts to stimulate the retinal nerveswith electrical signals, which are being conducted by various groupsglobally. For example, the Argus™ II implantable device, by Second SightMedical Products, Inc., 12744 San Fernando Road—Building 3, Sylmar,Calif. 91342, USA, which is intended to treat profoundly blind peoplesuffering from degenerative diseases such as RP. The Second SightMedical Products, Inc. Argus™ II system works by converting video imagescaptured from a miniature camera, housed in the patient's glasses, intoa series of small electrical pulses that are transmitted wirelessly toan epiretinal prosthesis array of electrodes implanted inside the eye onthe retina. These pulses then stimulate the retina's remaining cellsresulting in the corresponding perception of patterns of light in thebrain. Patients supposedly learn to interpret these visual patternsthereby gaining some functional vision.

U.S. Pat. No. 7,079,900 issued Jul. 18, 2006, to Greenburg et al.,titled “Electrode Array for Neural Stimulation,” is incorporated hereinby reference. Greenburg et al. describe a retinal color prosthesis torestore color vision by electrically stimulating undamaged retinalcells, which remain in patients with lost or degraded visual function.There are three main parts: one is external to the eye, the second partis internal to the eye, and the third part communicates between thosetwo parts. The external part has color imaging means (CCD or CMOS videocamera), an eye-tracker, a head-motion tracker, a data processor, apatient's controller, a physician's local controller, a physician'sremote controller, and a telemetry means. The color data is processed inthe video data processing unit and encoded by time sequences of pulsesseparated by varying amounts of time, and also with the pulse durationbeing varied in time. The basis for the color encoding is the individualcolor code reference. Direct color stimulation is another operationalbasis for providing color perception. The electrodes stimulate thetarget cells so as to create a color image for the patient,corresponding to the original image as seen by the video camera. Thephysician's test unit can be used to set up or evaluate and test theimplant during or soon after implantation.

U.S. Pat. No. 7,914,842 issued Mar. 29, 2011, to Greenberg et al.,titled “Method of Manufacturing a Flexible Circuit Electrode Array,” isincorporated herein by reference. Greenberg et al. describe polymermaterials and electrode array bodies for neural stimulation, especiallyfor retinal stimulation to create vision. The method lays down a polymerlayer, applies a metal layer to the polymer and pattern to createelectrodes and leads, and applies a second polymer layer over the metallayer and pattern to leave openings for electrodes. The array and itssupply cable are a single body.

Electrical stimulation represents a major challenge in developingimplantable devices with long-term system performance while reducingtheir overall size. The Boston Retinal Implant Project has identifiedlong-term biocompatibility as one of the most significant challenges tobe met in order to develop a successful retinal prosthesis. For example,U.S. Pat. No. 6,324,429 issued Nov. 27, 2001, to Shire et al., titled“Chronically Implantable Retinal Prosthesis,” is incorporated herein byreference. Shire et al. describe a chronically implantable retinalprosthesis for the blind which will restore some useful vision topatients over at least several degrees of their former field of view.These thin, strong, and flexible epiretinal devices are constructed ofor encapsulated in known biocompatible materials which will have a longworking life in the eye's saline environment. The function of theimplants is to electrically stimulate the ganglion cell layer at thesurface of the retina using controlled current sources. Due to theexceptionally low mass of the implant and its flexible, nearly planarform, patient discomfort and fluid drag caused by the implant minimized.These physical attributes also substantially reduce the potential ofharm to the most delicate structure of the eye, the retina, andtherefore enhance the long term safety and biocompatibility of thedevice. Since no micro-cables are required to be attached to the device,and its overall form and edges are rounded, the device is not expectedto stress the retina during chronic implantation. A provision is alsomade for nutrients to reach the retinal cells underneath the device toassure their long-term health.

U.S. Pat. No. 7,908,010 issued Mar. 15, 2011, to Greenberg et al.,titled “Retinal Prosthesis with Side Mounted Inductive Coil,” isincorporated herein by reference. Greenberg et al. describe a retinalprosthesis with an inductive coil mounted to the side of the eye bymeans of a strap around the eye. This allows for close coupling to anexternal coil and movement of the entire implanted portion with movementof the eyeball.

Electrical stimulation, as described in the above devices and patents,is limited since the spread of electricity does not allow separate orindependent stimulation of individual retinal nerve cells or evensmall-enough groups of nerve cells. Electrical stimulation thus greatlylimits the number of separately stimulated sites that are possible.Additionally, the electrical-stimulation approach will requireimplantation of a powered (e.g., an electrically powered) device, whichhas significant, difficult issues associated with obtaining power intothe eye and using the power by devices in the eye.

Other work is being done in the area of optogenetics wherein a virus isused to genetically sensitize nerve cells to certain wavelengths oflight, e.g., PCT publication WO 2010/011404 A2 titled “Vectors forDelivery of Light-Sensitive Proteins and Methods of Use,” which isincorporated herein by reference. This area may have some potential,however it will require significant development work, it involvesinjecting a virus into nerve tissue (which may have significant sideeffects and FDA-approval issues), and the virus is only partially takenup by nerve cells.

Materials that are compatible with the eye are described in U.S. Pat.No. 6,254,637 to Jin Hak Lee et al., titled “Artificial Cornea andImplantation Thereof”; U.S. Pat. No. 6,391,055 to Yoshito Ikada et al.,titled “Artificial Cornea”; U.S. Pat. No. 6,976,997 to Noolandi et al.,titled “Artificial Cornea”; U.S. Pat. No. 7,857,849 to David Myung etal., titled “Artificial corneal implant”; and U.S. Pat. No. 7,909,867 toDavid Myung et al., titled “Interpenetrating Polymer Network HydrogelCorneal Prosthesis”; each of which is incorporated herein by referencein its entirety.

Numerous digital light projection micro-electro-mechanical-system (MEMS)devices exist. For example, U.S. Pat. No. 4,566,935 issued to Hornbeckon Jan. 28, 1986, titled “Spatial Light Modulator and Method” and isincorporated herein by reference in its entirety. Hornbeck describedmethods of fabrication of spatial light modulators with deflectablebeams by plasma etching after dicing of a substrate into chips, each ofthe chips an SLM. Various architectures available with such plasmaetching process were disclosed and include metal cloverleafs forsubstrate addressing, metal flaps formed in a reflecting layer over aphotoresist spacer layer, and torsion hinged flaps in a reflectinglayer.

As another MEMS display example, U.S. Pat. No. 7,776,631 issued to Mileson Aug. 17, 2010, titled “MEMS Device and Method of Forming a MEMSDevice,” and is incorporated herein by reference in its entirety. Milesdescribed light in the visible spectrum being modulated using an arrayof modulation elements, and control circuitry connected to the array forcontrolling each of the modulation elements independently, each of themodulation elements having a surface which is caused to exhibit apredetermined impedance characteristic to particular frequencies oflight.

U.S. Pat. No. 7,177,081 issued to Tomita et al. on Feb. 13, 2007, titled“High Contrast Grating Light Valve Type Device,” and is incorporatedherein by reference in its entirety. Tomita et al. describe a gratinglight valve with a plurality of spaced reflective ribbons that arespatially arranged over a substrate with reflective surfaces. Thegrating light valve is configured to optimize the conditions forconstructive and destructive interference with an incident light sourcehaving a wavelength λ. The grating light valve preferably has a set ofmovable active ribbons alternating between the set of stationary biasribbons. In operation, active ribbons are moved by a multiple of λ/4 toswitch between the conditions for constructive and destructiveinterference.

U.S. Pat. No. 4,720,189 issued Jan. 19, 1988 to Heynen et al., titled“Eye-Position Sensor,” is incorporated herein by reference in itsentirety. Heynen et al. describe an eye-position sensor for use in aneye-activated optical transducer in which a spatial filter is used tomodify light reflected from the eye to form a substantially rectangularpattern on a quadrantal array of contiguous sensors. This arrangementprovides a substantially linear change in the output signal from thesensors in response to an equivalent movement of the eye.

U.S. Pat. No. 6,055,110 issued Apr. 25, 2000, to Kintz et al., titled“Compact Display System Controlled by Eye Position Sensor System,” isincorporated herein by reference in its entirety. Kintz et al. describea virtual image display system is provided which is made thinner throughthe use of an immersed beam splitter, and in one embodiment, totalinternal reflection. The display system includes an imaging surface onwhich a source object is formed, a first optical element having areflective function and a magnification function, a second opticalelement having a magnification function and an immersed beam splittingelement positioned between the first and second optical elements, theimmersed beam splitting element including a beam splitter surrounded byan optically transparent material having a refractive index greater thanair. An illumination source projects the source object formed at theimaging surface through the optically transparent material to the beamsplitter. The beam splitter reflects the projected source object to thefirst optical element. The first optical element magnifies the projectedsource object and reflects a magnified virtual image of the projectedsource object to the beam splitter. The magnified virtual imagetraverses the beam splitter to the second optical element whichmagnifies the magnified virtual image to produce a compound magnifiedvirtual image of the source object.

There remains a need in the art for an improved prosthesis and methodfor stimulating vision nerves to obtain a vision sensation that is moreuseful for the patient.

BRIEF SUMMARY OF THE INVENTION

The present invention uses infrared nerve stimulation (INS) technologythat uses infrared light to cause action potentials in nerve cells inthe eye. In recent years, optical-stimulation technology has beendeveloped to stimulate nerves. This INS technology can achieve muchhigher precision and selectivity of stimulation than using electricalcurrent to trigger nerve action potentials. In some embodiments, thepresent technology uses pulsed, infrared lasers to excite the neuraltissue next to the retina directly and without tissue damage. The adventof this technology represents a paradigm shift in artificial nervestimulation because it allows a high degree of spatial selectivity ofneural stimulation without the need for tissue contact.

The present invention provides an improved prosthesis and method forstimulating vision nerves to obtain a vision sensation that is usefulfor the patient that has lost vision due to AMD, RP, and other diseases.The invention utilizes infrared light to cause action potentials in theretinal nerves similar to those action potentials that result from rodsand cones stimulated by visible light in healthy retinas. In a relatedinvention by one of the inventors of the present invention, aneyeglass-mounted system is described that collects visual informationand converts it into a stimulation pattern which is projected into theeye at an infrared wavelength with the purpose of causing an actionpotential in the retinal nerves with the purpose of recreating sight. Asthe infrared light stimulation wavelengths are normally stronglyabsorbed by the vitreous humor and tissues of the eye, in someembodiments the invention provides a pathway or “image pipe” fortransmitting a stimulation pattern of infrared nerve-stimulation light,from an external infrared-light-emitting stimulator array, through theeye and focusing the stimulation pattern of infrared light on the nervesof the retina, especially the macula and fovea. In some embodiments, theinvention provides improved resolution down to a group of nerves, oreven the individual nerve level, with sufficient energy density so as tocause desired action potentials in the targeted nerves.

In some embodiments, a laser diode emitting light with a 1.87-micronwavelength stimulates nerves. This wavelength is important becausedevices capable of generating this wavelength are more available thanlonger mid-IR wavelengths. In some embodiments, laser-diode light of a2.1-micron wavelength is used for nerve stimulation. Laser diodes thatemit 2.1-micron-wavelength light are currently in research and wouldmost likely work as well as other wavelengths, since this wavelength,when generated by a lamp-pumped solid-state laser, has been shown to beeffective in stimulating nerves. In some embodiments, a laser-diodedevice (having one or more emitters) outputs light that is used fornerve stimulation, wherein the light has a wavelength of between about1.5 microns and about 6 microns; in various embodiments, for example,the wavelength is in the far infrared at about 1.5 microns, or about1.51 microns, about 1.52 microns, about 1.53 microns, about 1.54microns, about 1.55 microns, about 1.56 microns, about 1.57 microns,about 1.58 microns, about 1.59 microns, about 1.6 microns, about 1.61microns, about 1.62 microns, about 1.63 microns, about 1.64 microns,about 1.65 microns, about 1.66 microns, about 1.67 microns, about 1.68microns, about 1.69 microns, about 1.7 microns, about 1.71 microns,about 1.72 microns, about 1.73 microns, about 1.74 microns, about 1.75microns, about 1.76 microns, about 1.77 microns, about 1.78 microns,about 1.79 microns, about 1.8 microns, about 1.81 microns, about 1.82microns, about 1.83 microns, about 1.84 microns, about 1.85 microns,about 1.86 microns, about 1.87 microns, about 1.88 microns, about 1.89microns, about 1.9 microns, about 1.91 microns, about 1.92 microns,about 1.93 microns, about 1.94 microns, about 1.95 microns, about 1.96microns, about 1.97 microns, about 1.98 microns, about 1.99 microns,about 2.0 microns, about 2.01 microns, about 2.02 microns, about 2.03microns, about 2.04 microns, about 2.05 microns, about 2.06 microns,about 2.07 microns, about 2.08 microns, about 2.09 microns, about 2.1microns, about 2.11 microns, about 2.12 microns, about 2.13 microns,about 2.14 microns, about 2.15 microns, about 2.16 microns, about 2.17microns, about 2.18 microns, about 2.19 microns, about 2.2 microns,about 2.21 microns, about 2.22 microns, about 2.23 microns, about 2.24microns, about 2.25 microns, about 2.26 microns, about 2.27 microns,about 2.28 microns, about 2.29 microns, about 2.3 microns, about 2.31microns, about 2.32 microns, about 2.33 microns, about 2.34 microns,about 2.35 microns, about 2.36 microns, about 2.37 microns, about 2.38microns, about 2.39 microns, about 2.4 microns, about 2.5 microns, about2.6 microns, about 2.7 microns, about 2.8 microns, about 2.9 microns,about 3 microns, about 3.1 microns, about 3.2 microns, about 3.3microns, about 3.4 microns, about 3.5 microns, about 3.6 microns, about3.7 microns, about 3.8 microns, about 3.9 microns, about 4 microns,about 4.1 microns, about 4.2 microns, about 4.3 microns, about 4.4microns, about 4.5 microns, about 4.6 microns, about 4.7 microns, about4.8 microns, about 4.9 microns, about 5 microns, about 5.1 microns,about 5.2 microns, about 5.3 microns, about 5.4 microns, about 5.5microns, about 5.6 microns, about 5.7 microns, about 5.8 microns, about5.9 microns, or about 6.0 microns, or, in other embodiments, in rangesbetween any two of the above values. In other embodiments, an LED havingoutput wavelengths centered in one of these ranges is used as a sourceof light to stimulate nerves.

In some embodiments, the implant includes a material which is bothbiocompatible in the eye and highly transmissive at the infraredstimulation wavelengths. In some embodiments, the implant includesoptics that focus, collimate, and/or guide the stimulation light. Insome embodiments, the implant is sewn, stapled, or otherwise secured atthe sclera and/or sewn, stapled, or otherwise secured to those locationswhere the eye's natural lens is normally attached. In some embodiments,the implant is totally encapsulated within the eye, while in some otherembodiments, the implant extends through the cornea and/or sclera. Insome embodiments, the ocular implant uses materials and design featuresalready used in artificial corneas and intraocular lenses, for example,such as described in U.S. Pat. No. 6,254,637 to Jin Hak Lee et al.,titled “Artificial Cornea and Implantation Thereof”; U.S. Pat. No.6,391,055 to Yoshito Ikada et al., titled “Artificial Cornea”; U.S. Pat.No. 6,976,997 to Noolandi et al., titled “Artificial Cornea”; U.S. Pat.No. 7,857,849 to David Myung et al., titled “Artificial cornealimplant”; and U.S. Pat. No. 7,909,867 to David Myung et al., titled“Interpenetrating Polymer Network Hydrogel Corneal Prosthesis”; each ofwhich is incorporated herein by reference in its entirety.

In some embodiments, once surgically implanted in the eye, the ocularimplant has no internal moving parts relative to the eyeball and nointernal electrical parts. Thus, such an ocular implant requires nointernal or external electrical-power source. Additionally, the ocularimplant does not impede movement of the eyeball after surgicalimplantation. In some embodiments, the freedom of eye movement relativeto the external stimulator light can help provide enhanced patientcomfort and enhanced perceived image resolution.

In some embodiments, the present invention provides a VCSEL arrayconfigured to output light pulses capable of optically stimulatingneural tissue (e.g., cochlear nerve tissue, deep brain tissue, whitebrain matter tissue, gray brain matter tissue, spinal cord tissue,cardial nerve tissue, central nervous system nerve tissue, olfactorynerve tissue, optic nerve tissue, nerve bundles and the like). In someembodiments, the stimulating lights pulses have a wavelength thatresults in the appropriate penetration depth for effective stimulationof the tissue of interest without causing tissue damage (e.g., in someembodiments, the wavelength of stimulating light pulses is in the rangeof about 1.8 microns to about 2.2 microns, in some embodiments, thewavelength of stimulating light pulses is in the range of about 1.85microns to about 2.0 microns, in some embodiments, the wavelength ofstimulating light pulses is about 1.87 microns, in some otherembodiments the wavelength of stimulating light pulses is in the rangeof about 4.0 microns to about 5.0 microns, in some other embodiments thewavelength of stimulating light pulses is in the range of about 4.2microns to about 4.8 microns, in some other embodiments the wavelengthof stimulating light pulses is in the range of about 4.4 microns toabout 4.6 microns).

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1A is a cut-away perspective view of an eye 90 that illustrates animplanted ocular unit 100 according to some embodiments of theinvention.

FIG. 1B is a side cross-section view of an eye 90 that illustrates animplanted ocular unit 100, similar to FIG. 1A, according to someembodiments of the invention.

FIG. 2A is a side cross-section view of an eye 90 that illustrates animplanted intraocular unit 201 according to some embodiments of theinvention.

FIG. 2B is a side cross-section view of an eye 90 that illustrates animplanted intraocular unit 202 according to some embodiments of theinvention.

FIG. 2C is a side cross-section view of an eye 90 that illustrates animplanted intra-ocular unit 203 according to some embodiments of theinvention.

FIG. 2D is a side cross-section view of an eye 90 that illustrates animplanted intra-ocular unit 204 having an embedded optical-fiber bundle,according to some embodiments of the invention.

FIG. 3 is a side cross-section view of an eye 90 that illustrates animplanted ocular unit 300 according to some embodiments of theinvention.

FIG. 4 is a side cross-section view of an eye 90 that illustrates animplanted ocular unit 400 according to some embodiments of theinvention.

FIG. 5A is a side cross-section view of an eye 90 that illustrates animplanted ocular unit 501 according to some embodiments of theinvention.

FIG. 5B is a side cross-section view of an eye 90 that illustrates animplanted ocular unit 502 according to some embodiments of theinvention.

FIG. 5C is a side cross-section view of an eye 90 that illustrates animplanted ocular unit 503 according to some embodiments of theinvention.

FIG. 6 is a side cross-section view of an eye 90 that illustrates animplanted ocular unit 600 according to some embodiments of theinvention.

FIG. 7 is a side cross-section view of a retina 97.

FIG. 8A is a side cross-section view of a stimulation system 801 thatuses a single-depth VCSEL array 887 and a holographic imager 811.

FIG. 8B is a side cross-section view of a stimulation system 802 thatuses a VCSEL array 888 having a plurality of depths and a holographicimager 812.

FIG. 9 is a graph showing the absorption of light by PMMA at variouswavelengths.

FIG. 10 is a graph showing two sets of measurements of the absorption oflight by 0.5 mm of water at wavelengths of light between 1000 and 2100nm (infrared).

FIG. 11 is a graph of a water absorption factor of light at wavelengthsbetween 1.0 and 2.1 microns.

DETAILED DESCRIPTION OF THE INVENTION

Although the following detailed description contains many specifics forthe purpose of illustration, a person of ordinary skill in the art willappreciate that many variations and alterations to the following detailsare within the scope of the invention. Accordingly, the followingpreferred embodiments of the invention are set forth without any loss ofgenerality to, and without imposing limitations upon the claimedinvention. Further, in the following detailed description of thepreferred embodiments, reference is made to the accompanying drawingsthat form a part hereof, and in which are shown by way of illustrationspecific embodiments in which the invention may be practiced. It isunderstood that other embodiments may be utilized and structural changesmay be made without departing from the scope of the present invention.

The leading digit(s) of reference numbers appearing in the Figuresgenerally corresponds to the Figure number in which that component isfirst introduced, such that the same reference number is used throughoutto refer to an identical component which appears in multiple Figures.Signals and connections may be referred to by the same reference numberor label, and the actual meaning will be clear from its use in thecontext of the description.

FIG. 1A is a cut-away perspective view of a nerve-stimulation system 101for an eye 90 that illustrates an implanted ocular unit 100, accordingto some embodiments of the invention. In some embodiments, the ocularunit 100 includes a light-transparent pathway or “image pipe” 110 (whichincludes an optional lens system 116 and a transparent body 111) fortransmitting a stimulation pattern of infrared light 130 from anexternal stimulator array 180 through the eye 90 along optical path 199,the ocular unit 100 having a light-receiving anterior end 112 closest tothe eye's anterior surface and extending to a posterior end 114 of imagepipe 110 closer to the fovea 96 than to the eye's anterior surface,transmitting light and/or projecting image 122 onto the retina 97,including onto the macula 95 and fovea 96. In some embodiments, thecurved anterior surface of image pipe 110 acts as the anterior-endfocussing element and no separately formed lens 116 is needed.

As used herein, an “image pipe” is an optical device that forms an imagejust beyond its posterior end (e.g., when an image pipe of the presentinvention is implanted in the eye, the image is formed on the nerves atthe anterior surface of the retina) that is based on light 130 enteringthe anterior end. In some embodiments, an image pipe includes internalimaging components such as lenses, holographs, fiber optics orfiber-optic bundles, or the like, which assist in providing a focussedimage at the retina. In other embodiments, the image pipe is simply atransparent path that allows external imaging components to form theimage on the nerves at the front surface of the retina. Because someembodiments of the present invention use single-wavelength infraredlasers, holographic imagers are well suited to form images through suchan image pipe.

In some embodiments, the image pipe 110 is substantially transparent toat least some infrared wavelengths of light between about 1000 nm andabout 2000 nm, and in particular, is substantially transparent to thoseinfrared wavelengths output by the source lasers of the stimulationapparatus. In some embodiments, the image pipe 110 has a substantiallycylindrical shape such as shown in FIG. 1A, such that both ends of theimage pipe 110 have substantially the same diameter. In someembodiments, the image pipe 110 is formed from abiocompatible-transparent-thermoplastic material such as poly(methylmethacrylate) (PMMA), or the like. In some embodiments, such as shown inFIG. 1A, the light-receiving anterior end 112 of ocular unit 100replaces at least a portion of the cornea 99 of the eye and thus formspart of the anterior surface of the eye.

Poly(methyl methacrylate) (PMMA) is a transparent thermoplastic. PMMAhas been sold under many different names including Plexiglas®, Lucite®and Perspex®. PMMA is substantially transparent (i.e., a given thicknessof about a centimeter or more passes a majority of incident light) tovisible light (having wavelengths of 400 nm to 700 nm) and infraredlight (IR) having wavelengths from about 700 nm to about 2800 nm.Colored or tinted PMMA varieties allow specific IR wavelengths to passwhile blocking visible light and/or other IR wavelengths.

In some embodiments, ocular unit 100 is surgically secured in place tothe cornea 99 and/or sclera 98 in the eye with anchoring collar 140 andhydrogel skirt 150. In some embodiments, the implant is sewn (or stapledor otherwise anchored) to the ciliary muscle or secured to otherinternal parts of the eye to hold it securely in place. Ocular unit 100extends well into the vitreous humor 94, which is less transparent thanis image pipe 110 to certain infrared light wavelengths useful for nervestimulation.

The posterior end 114 of the image pipe 110 is closer to the fovea thanthe front of the eye. In some embodiments, image pipe 110 has a lengthsuch that the posterior end 114 of the image pipe 110 is near the retina97 in the region of the macula 95 and fovea 96. In some embodiments, theimage pipe 110 does not contact the retina 97, in order to leave apathway for the vitreous humor 94 to circulate and nourish the cells ofthe retina. In some embodiments, the posterior end 114 is positionedclose enough to the retina 97 and fovea 96 such that the remainingvitreous humor is thin enough and transparent enough that infrared lightoutput from the posterior end of the image pipe 110 will be sufficientlyintense to cause retinal-nerve stimulation (i.e., triggering of nerveaction potentials in the nerves of the retina due to impinging pulses ofinfrared light).

In some embodiments, the ocular image pipe 110 is solid material. PMMAhas a higher density than the vitreous humor. To more closely match thedensity of the vitreous humor, some embodiments of image pipe 110include at least one hollow portion such that the overall density of theimage pipe 110 is the same as the density of the surrounding vitreoushumor and the center of mass of the image pipe 110 coincides with thecenter of rotation of the eye, in order that the image pipe 110 does nottend to move relative to the eye with movement. In some embodiments, thehollow portion is filled with an inert gas. In some embodiments, thehollow portion is filled with a low-pressure gas having a pressure of nomore than about 1000 Torr. In some embodiments, the hollow portion is inthe light path of the light path and at least one end of the hollowportion is shaped to form a lens to focus the infrared light on nervesof the retina.

The placement, size, and shape of the hollow portion in the image pipe110 is used in some embodiments to not only match the density of thevitreous humor but to also control the center of gravity to help providea more stable implant the is resistant to movement of the head oreyeball. In some embodiments, the light-transmitting portion of imagepipe 110 is solid material and the hollow portion is formed in aperipheral portion outside and surrounding the light-transmitting path.This configuration reduces the number of optical interfaces in the lightpath. In some embodiments, the light-transmitting portion of image pipe110 is solid material and the hollow portion is formed symmetricallyaround a peripheral portion outside and surrounding thelight-transmitting path, such that regardless of whether the person'shead is upright or is lying on one side, there is no rotational or otherforce acting to move the implant (i.e., image pipe 110) relative to theeye. In other embodiments, the hollow portion is formed in (or is veryslightly larger in) a top portion of image pipe 110, in order to helpkeep the image pipe 110 upright and in the desired position when thepatient's head is upright.

In some embodiments, one or both ends of the image pipe 110 are shapedto focus the external stimulator light signals 130 on the retina andfovea. In some embodiments, there is an external light source 180 thatemits IR-wavelength stimulation light 130. For example, in someembodiments, source 180 includes a two-dimensional array ofvertical-cavity surface-emitting lasers (VCSEL-array) that form an IRstimulator, which provides IR light 130 into the anterior end 112 of theocular implant 100. In some embodiments, the user has an ocular unit 100implanted in each eye, and the system provides there is a separateexternal two-dimensional array IR stimulator source 180 for each eye,wherein the two separate images help provide three-dimensional images tothe brain through each eye's ocular unit 100. In some embodiments, imagepipe 110 includes a lens or lens system 116, with a different index ofrefraction than the rest of image pipe 110, to focus the image on theretina 97. In some embodiments, the lens system 116 inverts the incomingimage and focuses the image on the retina. In some other embodiments,the lens system 116 is noninverting and directs diverging, collimated,or converging light on the nerve-tissue layer of the retina 97. In someembodiments, the image pipe 110 and its lens 116, in combination with anexternal laser image-generation device 180 and its image processor(s)182 and one or more cameras in camera system 181, produce an infraredimage on the retina, similar to the inverted optical-wavelength image anormal human eye. Since the human brain will automatically accustomitself to any image consistently formed on the retina whether or not theimage is inverted, the camera system 181, image processor 182 andstimulation light sources 180 can be configured to form the image asinverted or not according to the preferences of the user. In someembodiments, camera system 181 includes at least one camera directedtoward the user's eye (e.g., to determine the locations of indicia 118and/or 119) to determine the location and/or direction of movement ofthe gaze of the user, and this image of the eye (or of the indicia118/119) is processed by image processor system 182 in order to controlthe position of the stimulation light sources that are generating thestimulation light signals 130, in order to position the projectedpattern of stimulation light onto the desired locations on retina 122.In some embodiments, the array of light sources 180 themselves arephysically moved to the desired position based on a detection of theposition of the eye (e.g., a flat VCSEL array mounted on a gimbal androtated on one or more axes by servos that are controlled by signalsbased on the detected eye position), while in other embodiments,different ones of the light sources 180 that are already in the desiredpositions relative to the eye are activated. In some embodiments,eye-position sensors (such as described in U.S. Pat. No. 4,720,189issued to Heynen et al. on Jan. 19, 1988, titled “Eye-Position Sensor,”and U.S. Pat. No. 6,055,110 issued to Kintz et al. on Apr. 25, 2000,titled “Compact Display System Controlled by Eye Position SensorSystem,” which are each incorporated herein by reference in itsentirety) detect a position of the eye (e.g., the direction to which theeye is pointing and/or the distance between the eye and thestimulation-light projector 180) and provide signals to a displaypositioning device (such as servo-controlled gimbals) that then movesone or more components of the stimulation-light projector 180 in orderto maintain a reference position of the display in a substantiallyconstant spatial relationship to the eye, and/or adjusts a focussingelement to maintain a focus of the IR-stimulation-light signals fromstimulation-light projector 180 onto the desired nerve layer of theretina. In some embodiments, a power source 183 is operatively coupledto supply power to operate the camera system 181, the image processorsystem 182, and the stimulation light sources 180.

In other embodiments, one or more grating light valves (such asdescribed in U.S. Pat. No. 7,177,081 titled “High Contrast Grating LightValve Type Device,” which is incorporated herein by reference in itsentirety) and/or one or more digital light projector devices (such asdescribed in U.S. Pat. No. 4,566,935 issued to Hornbeck on Jan. 28,1986, titled “Spatial Light Modulator and Method,” or U.S. Pat. No.7,776,631 titled “MEMS Device and Method of Forming a MEMS Device,”which are each incorporated herein by reference in its entirety) areused to modulate and/or direct light (e.g., from one or more lasers,LEDs or other suitable light-source devices) to desired locations.

In some embodiments, the ocular unit 100 has at least one indicia markto facilitate detection of the eye's position. In some embodiments, theocular unit has at least one indicia mark 118 on the anterior end tofacilitate external detection of the position of the eye and thepointing directions. In some embodiments, the ocular unit 100 has atleast one indicia mark 119 on the posterior end to facilitate externaldetection of the position of the eye and the pointing directions. Insome embodiments, one or more indicia marks are placed on both theanterior end posterior end, and/or on one or more other locations on theocular unit 100. In some embodiments the location and/or orientation ofthe implant is determined, for example, by obtaining an image of, ordetecting reflected or fluorescent light from, the indicia mark or marks118 and/or 119 and the external stimulator array signals are adjusted tocompensate for the position of the eye (e.g., the image or pattern ismoved such that the desired nerve tissue continues to be stimulated). Insome such embodiments, an eye-position processor in the external imageprocessor 182 uses an “inward-pointing” camera in camera system 181(i.e., a camera pointed toward the user to obtain an image of the eyeand/or indicia 118/119) to detect movement or position of the user'seye(s), and generates control signals that direct an external cameraview (i.e., the direction in which the camera system 181 is pointing, orif a very-wide-angle lens and/or multiple cameras are used, which of theimages obtained by camera system 181 is used), providing a morerealistic sensation of “looking around” to the user, instead ofrequiring movement of the user's entire head to obtain different images.In some embodiments, a plurality of “outward-pointing” cameras isincluded in camera system 181 (i.e., a plurality of cameras pointedtoward different directions in the environment surrounding user toobtain a plurality of images from which to select based on the detecteddirection of the user's gaze).

FIG. 1B is a side cross-section view of an eye 90 that illustrates theimplanted ocular unit 100, which is also shown in FIG. 1A, according tosome embodiments of the invention. In some embodiments, the ocular unit100 includes a light-transparent pathway or “image pipe” 110 fortransmitting a stimulation pattern of infrared light from an externalstimulator array through the eye, and a fastening mechanism (e.g.,anchoring collar 140 and hydrogel skirt 150) for attaching the ocularunit 100 to the eye 90. The image pipe 110 has a light-receivinganterior end 112 closest to the eye's anterior surface and extending toa posterior end 114 of image pipe 110 closer to the fovea 96 than to theeye's anterior surface.

In some embodiments of ocular unit 100 of FIGS. 1A and 1B the posteriorend 114 of image pipe 110 (and in some embodiments of the ocular unitsof FIGS. 2A, 2B, 3, 4, 5, and 6, the respective posterior ends of theirimage pipes) is within about 10 mm of the retina. In some embodiments,the posterior end of the image pipe is within about 8 mm of the retina.In some embodiments, the posterior end of the image pipe is within about5 mm of the retina. In some embodiments, the posterior end of the imagepipe is within about 4 mm of the retina. In some embodiments, theposterior end of image the pipe is within about 3 mm of the retina. Insome embodiments, the posterior end of image the pipe is within about 2mm of the retina. In some embodiments, the posterior end of image thepipe is within about 1 mm of the retina. In some embodiments, theposterior end of image the pipe is between about 1 cm and about 5 mm ofthe retina. In some embodiments, the posterior end of the image pipe isbetween about 5 mm and about 2 mm of the retina. In some embodiments ofthe ocular units of FIGS. 1A, 1B, 2A, 2B, 3, 4, 5, and 6, the light pathwithin the ocular unit is at least 50% of the total distance from theanterior surface of the eye to the retina. In some embodiments of theocular units of FIGS. 1A, 1B, 2A, 2B, 3, 4, 5, and 6, the light pathwithin the ocular unit is at least 70% of the total distance from theanterior surface of the eye to the retina. In some embodiments of theocular units of FIGS. 1A, 1B, 2A, 2B, 3, 4, 5, and 6, the light pathwithin the ocular unit is at least 80% of the total distance from theanterior surface of the eye to the retina. In some embodiments of theocular units of FIGS. 1A, 1B, 2A, 2B, 3, 4, 5, and 6, the light pathwithin the ocular unit is at least 90% of the total distance from theanterior surface of the eye to the retina. In some embodiments of theocular units of FIGS. 1A, 1B, 2A, 2B, 3, 4, 5, and 6, the light pathwithin the ocular unit is at least 95% of the total distance from theanterior surface of the eye to the retina.

Note that in some embodiments, it is the entire system includingexterior optics in the stimulation light source 180, along with the lenssystem 116 and body 110 of ocular unit 100 that act together to focusthe image onto the desired nerve-tissue layer of the retina 97.

FIG. 2A is a side cross-section view of an eye 90 that illustrates animplanted intra-ocular unit 201 according to some embodiments of theinvention. In some embodiments, ocular unit 201 is similar to ocularunit 100 except ocular unit 201 is fully contained intraocularly (i.e.,completely inside the eye) after being surgically implanted. In thisembodiment, the image pipe 210 is surgically secured in place in the eyewith the implant sewn, stapled, or otherwise secured 245 to the ciliarymuscle 93 or secured to other internal parts of the eye to hold itsecurely in place. In some such embodiments, the ocular unit 201 iscompletely contained within the eye and the user's cornea 99 ismaintained intact.

In some embodiments, the ocular unit 201 includes an image pipe 210 fortransmitting a stimulation pattern of infrared light from an externalstimulator array through the eye, the ocular unit 201 having alight-receiving anterior end 212 closest to the eye's anterior surface(behind the cornea) and extending to a posterior end 214 that is closerto the fovea than to the eye's anterior surface.

In some embodiments, the image pipe 210 is substantially transparent toat least some infrared wavelengths of light between about 1000 nm andabout 2000 nm. In some embodiments, the image pipe 210 is substantiallycylindrical-shaped such as shown in FIG. 2, such that both ends of theimage pipe 210 have substantially the same diameter. In someembodiments, the image pipe 210 is formed from abiocompatible-transparent-thermoplastic material such as poly(methylmethacrylate) (PMMA), or the like.

The posterior end 214 of the image pipe 210 is closer to the fovea thanthe front of the eye. In some embodiments, image pipe 210 has a lengthsuch that the posterior end 214 of the image pipe 210 is near the retina97 in the region of the fovea 96. In some embodiments, the image pipe210 does not contact the retina, in order to leave a pathway for thevitreous humor of the eye to circulate and nourish the cells of theretina. In some embodiments, the posterior end 214 is positioned closeenough to the retina 97 and fovea 96 such that the remaining vitreoushumor 94 is thin enough and transparent enough that infrared lightoutput from the posterior end of the image pipe 210 will be sufficientlyintense to cause retinal-nerve stimulation (i.e., triggering of nerveaction potentials in the nerves of the retina due to impinging pulses ofinfrared light).

In some embodiments, the ocular image pipe 210 is solid material. PMMAhas a higher density than the vitreous humor. To more closely match thedensity of the vitreous humor, some embodiments of image pipe 210include at least one hollow portion such that the overall density of theimage pipe 210 is the same as the density of the surrounding vitreoushumor and the center of mass of the image pipe coincides with the centerof rotation of the eye, in order that the image pipe 210 does not tendto move relative to the eye with movement. In some embodiments, thehollow portion is filled with an inert gas. In some embodiments, thehollow portion is filled with a low-pressure gas having a pressure of nomore than about 1000 Torr. In some embodiments, the hollow portion is inthe light path of the light path and at least one end of the hollowportion is shaped to form a lens to focus the infrared light on nervesof the retina.

The placement, size, and shape of the hollow portion in the image pipe210 is used in some embodiments to not only match the density of thevitreous humor but to also control the center of gravity to help providea more stable implant the is resistant to movement of the head oreyeball. In some embodiments, the light-transmitting portion of imagepipe 210 is solid material and the hollow portion is formed in aperipheral portion outside and surrounding the light-transmitting path.This configuration reduces the number of optical interfaces in the lightpath. In some embodiments, the light-transmitting portion of image pipe210 is solid material and the hollow portion is formed symmetricallyaround a peripheral portion outside and surrounding thelight-transmitting path, such that regardless of whether the person'shead is upright or is lying on one side, there is no rotational or otherforce acting to move the implant (i.e., image pipe 210) relative to theeye. In other embodiments, the hollow portion is formed in (or is veryslightly larger in) a top portion of image pipe 210, in order to helpkeep the image pipe 210 upright and in the desired position when thepatient's head is upright.

In some embodiments, one or both ends of the image pipe 210 are shapedto focus the externally generated stimulator-array signals on the retinaand fovea. In some embodiments, the present invention includes anexternal two-dimensional array VCSEL-array IR stimulator providing IRlight 130 into the anterior end of the ocular implant 201.

In other embodiments of any of the embodiments of the present inventionincluding the system described in FIG. 1A or FIG. 8A, other IR lightsources are used, such as LED array emitters, or one or more single IRlight sources that project light to an array modulator such as one ormore grating light valves (for example, as described in U.S. Pat. No.7,177,081 titled “High Contrast Grating Light Valve Type Device,” whichis incorporated herein by reference in its entirety) and/or one or moredigital light projector devices (such as described in U.S. Pat. No.4,566,935 issued to Hornbeck on Jan. 28, 1986, titled “Spatial lightmodulator and method,” or U.S. Pat. No. 7,776,631 titled “MEMS Deviceand Method of Forming a MEMS Device,” which are each incorporated hereinby reference in its entirety), wherein the array light modulatorprovides a modulated nerve-stimulation signal to each of a plurality oflocations on the patient's retina via the ocular implant 201. In yetother embodiments, any other suitable sources of IR stimulation lightare used, including light sources emitting from a plurality of heightsfrom their substrates (such as LED arrays or MEMS mirrors configured tofocus at a plurality of depths in the nerves of the retina, such asshown in FIG. 8B).

In some embodiments, there is an external two-dimensional array IRstimulator for each eye to help provide three-dimensional images to theuser with an ocular unit 201 implanted in each eye. In some embodiments,image pipe 210 includes a lens 216, with a different index of refractionthan the rest of image pipe 210, to focus the image on the retina 97. Insome embodiments, the lens 216 is a convex lens that has a higher indexof refraction than the surrounding tissue and/or the body 210 of ocularunit 201 (or is a concave lens that has a lower index of refraction) andlens 216 (along with any external lens(es) and the cornea 99) invertsthe incoming image and focuses the image on the retina. Note that insome embodiments, it is the entire system including exterior optics inthe light source 180 and the cornea of the eye, along with the lenssystem 216 that act together to focus the image onto the desired nervetissue. In some other embodiments, on the lens is noninverting anddirects collimated light on the retina. In some embodiments, the imagepipe 210, lens 216, in combination with an external laser-signalgeneration device produce an inverted nerve-stimulation pattern on theretina, similar to the inverted image a normal human eye.

In some embodiments, the ocular unit 201 has at least one indicia mark218, 219, and/or 220 to facilitate detection of the eye's position. Insome embodiments, the ocular unit has at least one anterior indicia mark118, posterior indicia mark 119, or both to facilitate externaldetection of the position of the eye and the pointing direction of thegaze used for controlling the camera system 181 (e.g., moving theposition/direction of the camera 181, or shifting the portion of theimage obtained from the camera 181 and used to generation thestimulation signals 130). In some embodiments, indicia marks are placedon one or more other locations on the ocular unit 100. In someembodiments, reflected light from the indicia mark or marks is detectedand the external stimulator array signals are adjusted to compensate forthe position of the eye.

FIG. 2B is a side cross-section view of an eye 90 that illustrates animplanted intra-ocular unit 202 according to some embodiments of theinvention. In some embodiments, the lens 217 is a concave lens that hasa higher index of refraction than the surrounding tissue and/or the body210 of ocular unit 201 (or is a convex lens that has a lower index ofrefraction) and does not invert the incoming image in order to projectthe image on the nerves in the anterior surface of the retina. Note thatin some embodiments, it is the entire system including exterior opticsin the light source 180 and the cornea of the eye, along with the lenssystem 217 that act together to focus the image onto the desired nervetissue.

FIG. 2C is a side cross-section view of an eye 90 that illustrates animplanted intra-ocular unit 203 according to some embodiments of theinvention. In some embodiments, ocular unit 203 is identical to ocularunit 201 of FIG. 2A, except for including one or more bubbles orair-filled pockets 222, located outside of the optical path 199 (e.g.,in some embodiments, along side of the focal point of the light focussedby lens 216) and used to provide a neutral buoyancy to ocular unit 203,so it neither floats toward the top of the eye 90, nor sinks toward thebottom of the eye 90, nor twists (e.g., up in back and down in front dueto the different material densities of the lens 216 and body 210). Insome embodiments, pockets 222 are coated with an opaque material, inorder that they serve as an aperture or spatial filter, blocking lightthat is not part of the focussed stimulation-light image. In someembodiments, pockets 222 have one or more indicia 220 located such thatan external camera can image the indicia and then determine the positionof the eye 90, but also located off to the side of the optical path 199such that the indicia do not interfere with or block any portion of theprojected image of the stimulation light. In some embodiments, pockets222 are formed of two or more separate bubbles located so as to providea center of gravity point and neutral buoyancy to minimize unwantedmovement of the ocular unit 203, while in other embodiments, atorus-shaped pocket surrounds a center portion of body 210 to providethis functionality. Further descriptions of such structures are providedbelow in the description of FIG. 4.

In other embodiments (not shown), an aperture that is not part of suchbubble features is provided in any of the embodiments described herein,where the aperture surrounds the expected focal point of the imagelight, to serve as a spatial filter, blocking light that is not part ofthe focussed stimulation-light image.

FIG. 2D is a side cross-section view of an eye 90 that illustrates animplanted intra-ocular unit 204 having an embedded optical-fiber bundle,according to some embodiments of the invention. In some embodiments, thebody of the intraocular unit 242 includes a plurality of optical fibers244 embedded in a carrier 243 of PMMA 243. Each optical fiber 244provides a separate optical path 199 through the intraocular unit 242.In some embodiments, the plurality of optical fibers 244 are arranged inan array that preserves the image aspect ratio. An image from the lightsource 130 is formed on the anterior end 212 of the intraocular implant,the image is conducted through the optical fibers 244, and the image isprojected from the posterior end 214 of the ocular implant onto theretinal nerves. In some embodiments, the optical fibers 244 aresubstantially parallel (e.g., the output image exiting the posterior end214 is the same size and shape as the input image entering at anteriorend 212). In other embodiments, the optical fibers 244 have varyingnon-parallel paths through the carrier 243 (e.g., in some embodiments,the optical fibers 244 themselves remain a constant-diameter size buttheir spacings increase towards the posterior end such that the fibersdiverge (gradually separate from one another towards the posterior end214) such that the height and/or width of the output image exiting theposterior end 214 is larger than the input image entering at anteriorend 212, while in other embodiments, in some embodiments, the opticalfibers converge (gradually get closer to one another) such that outputimage exiting the posterior end 214 is smaller than the input imageentering at anterior end 212). In some embodiments, a plurality ofoptical fibers 244 is gathered in a tight bundle, then one end is heatedand stretched away from the opposite end such that the stretched endbecomes smaller in diameter while preserving the aspect ratio of theimage that is transmitted through the bundle, but the size changes(becoming larger or smaller depending on which end the image enters),since the diameter of each fiber changes, and the diameter of the bundleas a whole changes.

In some embodiments, the body 242 of the intraocular implant is shapedsubstantially like a cylinder. In other embodiments (not shown, but in amanner similar to FIG. 3), the body 242 of the intraocular implant has asubstantially conical shape wherein the posterior end 214 of the body242 has a larger diameter than the anterior end 212 of the body 242. Infurther embodiments (not shown), the body 242 of the intraocular implanthas a substantially conical shape wherein the anterior end 212 of thebody 242 has a larger diameter than the posterior end 214 of the body242. In some embodiments, the optical fibers 244 are glass and arefabricated from a material that is substantially transparent (transmitsat least about 50% of the light energy) to wavelengths of light in theinfrared region of about 1000 nm to about 2100 nm (or at least in theportion of that infrared spectrum that is used by the stimulation lightsignal). In some embodiments, the optical fibers 244 are fabricated froma material that is substantially transparent (transmits at least about50% of the light energy) to wavelengths of light in the infrared regionof about 1600 nm to about 2000 nm. In some embodiments, the opticalfibers 244 are fabricated from a material that is substantiallytransparent to wavelengths of light in the infrared region of about 1700nm to about 1900 nm. In some embodiments, the optical fibers 244 arefabricated from a material that is substantially transparent towavelengths of light in the infrared region of about 1800 nm to about2000 nm. In some embodiments, the optical fibers 244 are fabricated froma material that is substantially transparent to wavelengths of light inthe infrared region of about 1800 nm to about 1900 nm.

FIG. 3 is a side cross-section view of an eye 90 that illustrates animplanted ocular unit 300 according to some embodiments of theinvention. In some embodiments the ocular unit 300 includes image pipe310 that has a substantially conical, or tapered, shape rather than thecylindrical shape (e.g., as shown in ocular unit 100 in FIGS. 1A and 1Band ocular unit 201 in FIG. 2A and ocular unit 202 of FIG. 2B) in orderto provide stimulating light over a larger area of the retina for awider field of view. In some such embodiments, the posterior end 314 ofthe transparent material of image pipe 310 has a diameter that is largerthan a diameter of the anterior end 312 of the transparent material. Insome embodiments, the ocular unit 300 includes a light-transparentpathway or “image pipe” 310 for transmitting a stimulation pattern ofinfrared light 130 from an external stimulator array through the eye,the ocular unit 300 having a light-receiving anterior end 312 closest tothe eye's anterior surface and extending to a posterior end 314 of imagepipe 310 closer to the fovea 96 than to the eye's anterior surface,projecting an image on the retina 97, including on the macula 95 andfovea 96.

In some embodiments, one or both ends of the image pipe 310 are shapedto focus the externally generated stimulator-array signals on the retinaand fovea. In some embodiments, there is an external two-dimensionalarray VCSEL-array IR stimulator providing IR light 130 into the anteriorend of the ocular implant 300. In some embodiments, there is an externaltwo-dimensional array IR stimulator for each eye to help providethree-dimensional images to the user with an ocular unit 300 implantedin each eye. In some embodiments, image pipe 310 includes a lens (see,for example, lens 216 of FIG. 2A) with a different index of refractionthan the rest of image pipe 310, to focus the image on the retina 97. Insome embodiments, the lens inverts the incoming image and focuses theimage on the retina. In some other embodiments, on the lens isnoninverting and directs collimated light on the retina. In someembodiments, the image pipe 310, lens, in combination with an externallaser-signal generation device produce an inverted nerve-stimulationpattern on the retina, similar to the inverted image a normal human eye.

In some embodiments, ocular unit 300 has the optional features of ocularunit 100 and intra-ocular unit 201, with the difference being theconical-shaped image pipe 310. In some embodiments, ocular unit 201includes a conical-shaped image pipe instead of the cylindrically shapedimage pipe 210 shown in FIG. 2A and FIG. 2B.

FIG. 4 is a side cross-section view of an eye 90 that illustrates animplanted ocular unit 400 according to some embodiments of theinvention. In some embodiments the ocular unit 400 includes image pipe410 that has a substantially cylindrical shape with an additionalwidened section including a doughnut-shaped (i.e., torus-shaped) hollowportion 422 that surrounds the longitudinal axis of the optical path199. In some such embodiments, the posterior end 414 of the transparentmaterial of image pipe 410 has a diameter about the same diameter as theanterior end 412 of the transparent material. In some embodiments, theocular unit 400 includes a light-transparent pathway or “image pipe” 410for transmitting a stimulation pattern of infrared light 130 from anexternal stimulator array through the eye, the ocular unit 400 having alight-receiving anterior end 412 closest to the eye's anterior surfaceand extending to a posterior end 414 of image pipe 410 closer to thefovea 96 than to the eye's anterior surface, projecting an image on theretina 97, including on the macula 95 and fovea 96.

To more closely match the density of the vitreous humor, someembodiments of image pipe 410 include at least one hollow portion 422such that the overall density of the image pipe 410 is the same as thedensity of the surrounding vitreous humor and the center of mass of theimage pipe 410 coincides with the center of rotation of the eye, inorder that the image pipe 410 does not tend to move relative to the eyewith movement. In some embodiments, the hollow portion 422 is filledwith an inert gas. In some embodiments, the hollow portion is filledwith a low-pressure gas having a pressure of no more than about 1000Torr.

The placement, size, and shape of the hollow portion in the image pipe410 is used in some embodiments to not only match the density of thevitreous humor but to also control the center of gravity to help providea more stable implant the is resistant to movement of the head oreyeball. In some embodiments, the light-transmitting portion of imagepipe 410 is solid material and the hollow portion is formed in aperipheral portion outside and surrounding the light-transmitting path.This configuration reduces the number of optical interfaces in the lightpath. In some embodiments, the light-transmitting portion of image pipe410 is solid material and the hollow portion 422 is formed symmetricallyaround a peripheral portion outside and surrounding thelight-transmitting path, such that regardless of whether the person'shead is upright or is lying on one side, there is no rotational or otherforce acting to move the implant (i.e., image pipe 410) relative to theeye. In other embodiments, the hollow portion is formed in (or is veryslightly larger in) a top portion of image pipe 410, in order to helpkeep the image pipe 410 upright and in the desired position when thepatient's head is upright.

In some embodiments, image pipe 410 includes a lens 416, with adifferent index of refraction than the rest of image pipe 410, to focusthe image on the retina 97. In some embodiments (as shown by lens 216 inFIG. 2C), the lens inverts the incoming image and focuses the imagethrough a focal point and onto the retina. In some other embodiments (asshown in FIG. 4), the lens 416 is noninverting and directs collimatedlight on the retina. In still other embodiments, the lens isnoninverting and directs diverging light (such as the lens 217 shown inFIG. 2B), or converging light (embodiments not shown herein) on theretina. In some embodiments, the image pipe 410, lens 416, incombination with an external laser-signal generation device produce aninverted nerve-stimulation pattern on the retina, similar to theinverted image a normal human eye.

In some embodiments, ocular unit 400 is fully contained intraocularly(i.e., completely inside the eye similar to ocular unit 201 of FIG. 2A)after being surgically implanted. In some such embodiments, the imagepipe 410 is surgically secured in place in the eye with the implantsewn, stapled, or otherwise secured to the ciliary muscle or secured toother internal parts of the eye to hold it securely in place. In somesuch embodiments, the ocular unit 400 is completely contained within theeye and the user's cornea 99 is maintained intact.

FIG. 5A is a side cross-section view of an eye 90 that illustrates animplanted ocular unit 501 according to some embodiments of theinvention. In some embodiments the ocular unit 501 includes image pipe510 that has a substantially cylindrical shape with a short hollowcenter portion 522A. In some such embodiments, the posterior end 514 ofthe transparent material of image pipe 510 has a diameter about the samediameter as the anterior end 512 of the transparent material. In someembodiments, the ocular unit 501 includes a light-transparent pathway or“image pipe” 510 for transmitting a stimulation pattern of infraredlight 130 from an external stimulator array through the eye, the ocularunit 501 having a light-receiving anterior end 512 closest to the eye'santerior surface and extending to a posterior end 514 of image pipe 510closer to the fovea 96 than to the eye's anterior surface, projecting animage on the retina 97, including on the macula 95 and fovea 96.

To more closely match the density of the vitreous humor, someembodiments of image pipe 510 include at least one hollow portion 522Asuch that the overall density of the image pipe 510 is the same as thedensity of the surrounding vitreous humor and the center of mass of theimage pipe 510 coincides with the center of rotation of the eye, inorder that the image pipe 510 does not tend to move relative to the eyewith movement. In some embodiments, the hollow portion 522A is filledwith an inert gas. In some embodiments, the hollow portion 522A isfilled with a low-pressure gas having a pressure of no more than about1000 Torr.

The placement, size, and shape of the hollow portion 522A in the imagepipe 510 is used in some embodiments to not only match the density ofthe vitreous humor but to also control the center of gravity (e.g., tobalance relative to the mass of lens 516) to help provide a more stableimplant the is resistant to movement of the head or eyeball. In someembodiments, the light-transmitting portion of image pipe 510 is solidmaterial and the hollow portion is formed in a central portion of thelight-transmitting path. In other embodiments, the hollow portion isformed in (or is very slightly larger in) a top portion of image pipe110, in order to help keep the image pipe 510 upright and in the desiredposition when the patient's head is upright.

In some embodiments, image pipe 510 includes a lens 516, with adifferent index of refraction than the rest of image pipe 510, to focusthe image on the retina 97. In some embodiments, the lens inverts theincoming image and focuses the image on the retina. In some otherembodiments, on the lens is noninverting and directs collimated light onthe retina. In some embodiments, the image pipe 510, lens 516, incombination with an external laser-signal generation device 180 producean inverted nerve-stimulation pattern on the retina, similar to theinverted image a normal human eye.

In some embodiments, ocular unit 501 is fully contained intraocularly(i.e., completely inside the eye similar to ocular unit 201) after beingsurgically implanted. In some such embodiments, the image pipe 510 issurgically secured in place in the eye with the implant sewn, stapled,or otherwise secured to the ciliary muscle or secured to other internalparts of the eye to hold it securely in place. In some such embodiments,the ocular unit 501 is completely contained within the eye and theuser's cornea 99 is maintained intact.

FIG. 5B is a side cross-section view of an eye 90 that illustrates animplanted ocular unit 502 according to some embodiments of theinvention. In some embodiments the ocular unit 502 includes image pipe510 that has a substantially cylindrical shape with a long hollow centerportion 522B. In some embodiments, implanted ocular unit 502 issubstantially similar to ocular unit 501 of FIG. 5A described above,except that ocular unit 502 has a longer hollow center portion 522B.

FIG. 5C is a side cross-section view of an eye 90 that illustrates animplanted ocular unit 503 according to some embodiments of theinvention. In some embodiments the ocular unit 503 includes image pipe510 that has a substantially cylindrical shape with a long hollow centerportion 522B. In some embodiments, implanted ocular unit 503 issubstantially similar to ocular unit 502 of FIG. 5B, except that ocularunit 503 is implanted entirely within the eye 90 as was the case withocular unit 203 of FIG. 2C described above.

FIG. 6 is a side cross-section view of an eye 90 that illustrates animplanted ocular unit 600 according to some embodiments of theinvention. In some embodiments the ocular unit 600 includes image pipe610 that has a substantially conical shape with an additional widenedsection including a doughnut-shaped hollow portion 622. In some suchembodiments, the posterior end 614 of the transparent material of imagepipe 610 has a diameter substantially larger than the diameter as theanterior end 612 of the transparent material. In some embodiments, theocular unit 600 includes a light-transparent pathway or “image pipe” 610for transmitting a stimulation pattern of infrared light 130 from anexternal stimulator array through the eye, the ocular unit 600 having alight-receiving anterior end 612 closest to the eye's anterior surfaceand extending to a posterior end 614 of image pipe 610 closer to thefovea 96 than to the eye's anterior surface, projecting an image on theretina 97, including on the macula 95 and fovea 96.

To more closely match the density of the vitreous humor, someembodiments of image pipe 610 include at least one hollow portion 622such that the overall density of the image pipe 610 is the same as thedensity of the surrounding vitreous humor and the center of mass of theimage pipe 610 coincides with the center of rotation of the eye, inorder that the image pipe 610 does not tend to move relative to the eyewith movement. In some embodiments, the hollow portion 622 is filledwith an inert gas. In some embodiments, the hollow portion is filledwith a low-pressure gas having a pressure of no more than about 1000Torr.

The placement, size, and shape of the hollow portion in the image pipe610 is used in some embodiments to not only match the density of thevitreous humor but to also control the center of gravity to help providea more stable implant the is resistant to movement of the head oreyeball. In some embodiments, the light-transmitting portion of imagepipe 610 is solid material and the hollow portion is formed in aperipheral portion outside and surrounding the light-transmitting path.This configuration reduces the number of optical interfaces in the lightpath. In some embodiments, the light-transmitting portion of image pipe610 is solid material and the hollow portion 422 is formed symmetricallyaround a peripheral portion outside and surrounding thelight-transmitting path, such that regardless of whether the person'shead is upright or is lying on one side, there is no rotational or otherforce acting to move the implant (i.e., image pipe 610) relative to theeye. In other embodiments, the hollow portion is formed in (or is veryslightly larger in) a top portion of image pipe 610, in order to helpkeep the image pipe 610 upright and in the desired position when thepatient's head is upright.

In some embodiments, image pipe 610 includes a lens (see, for example,lens 216 of FIG. 2A) with a different index of refraction than the restof image pipe 610, to focus the image on the retina 97. In someembodiments, the lens inverts the incoming image and focuses the imageon the retina. In some other embodiments, on the lens is noninvertingand directs collimated light on the retina. In some embodiments, theimage pipe 610, lens, in combination with an external laser-signalgeneration device produce an inverted nerve-stimulation pattern on theretina, similar to the inverted image a normal human eye.

In some embodiments, ocular unit 600 is fully contained intraocularly(i.e., completely inside the eye similar to ocular unit 600) after beingsurgically implanted. In some such embodiments, the image pipe 610 issurgically secured in place in the eye with the implant sewn, stapled,or otherwise secured to the ciliary muscle or secured to other internalparts of the eye to hold it securely in place. In some such embodiments,the ocular unit 600 is completely contained within the eye and theuser's cornea 99 is maintained intact.

FIG. 7 is a side cross-section view of a retina 97. In some embodiments,the present invention is used to stimulate nerve action potentialsdirectly in the ganglion nerves 85, the amacrine nerve cells 83, and/orthe bipolar nerve cells 82 of the retina 97. According to Frank Werblinand Botond Roska, in an article titled “The Movies in Our Eyes”(Scientific American, April 2007, pages 72-79), it appears that normallythe rod cells and cone cells 81 at the posterior wall 80 of the retina97 receive visible light (having wavelengths in the range of 400 to 700nm), and generate nerve signals to a plurality of synapses at the tipsof its axons. These signals from one rod or cone cell are received bythe bipolar cells 82 and amacrine cells 83 that are in direct contactwith the synapses of that rod or cone cell 81. They note thatresearchers have identified numerous types of bipolar cells 82, numeroustypes of amacrine cells 83, and numerous types of ganglion cells 85. Thebipolar cells generate excitory signals based on inputs from the rodsand cones to which each bipolar cell is connected, while the amacrinecells generate inhibitory signals based on inputs from the rods andcones to which each amacrine cell is connected. There are a plurality ofconnection layers in the inner plexiform layer 84, wherein at eachconnection layer has transmit ends of axons from various excitorybipolar cells and inhibitory amacrine cells, to which are connected thereceive ends of the ganglion cells. In some embodiments, differentsignals from the IR stimulation light are focussed on different ones ofeither ganglion, amacrine, or bipolar cells. When focussed on theganglion layer of cells 85, the IR stimulation light signals generatenerve action potentials (NAPs) directly in ones of those ganglion cells,which NAPs are then transmitted toward the optic nerve output of theeye. When focussed on the bipolar layer of cells 82, the IR stimulationlight signals generate excitory nerve action potentials (NAPs) directlyin ones of those bipolar cells, which excitory NAPs are then transmittedtoward one of the layers of interconnects in the inner plexiform layer84, where once they combine and reach a certain threshold they thentrigger a NAP in the respective ganglion cell(s). In contrast, whenfocussed on the amacrine layer of cells 83, the IR stimulation lightsignals generate inhibitory nerve action potentials (NAPs) directly inones of those amacrine cells, which inhibitory NAPs are then transmittedtoward one of the layers of interconnects in the inner plexiform layer84, where once they act to inhibit NAP in the respective ganglioncell(s). In some embodiments, the stimulation light signals aretransmitted from differing distances from the anterior (light-entry) endof the ocular implant, and thus they focus at differing distances fromthe posterior end of the ocular implant, and thus can be controlled asto which layer of nerve cells they will stimulate. Accordingly, NAPs canbe controllably and selectively triggered in different layers of nervecells in the retina, to thus generate NAPs that are either excitory(from the bipolar cell layer 82) or inhibitory (from the amacrine layerof cells 83) and those NAPS are then additively and/or subtractivelycombined in the inner plexiform layer to trigger output signals in theganglion cells connected to those inner plexiform layer connections, ordirectly output (from the ganglion layer of cells 85) when thestimulation light is focussed there.

In some embodiments, the external stimulation IR source outputs IR lightsignals that represent a pre-processed version of an image scene,wherein the preprocessing mimics or replicates the internal opticalprocessing of images normally performed by the millions ofinterconnections between the various cell layers of the retina. In someembodiments, the preprocessing needed is empirically determined byfocussing various patterns on different ones of the cells in the variousbipolar, amacrine and/or ganglion layers and having the subjects reportthe sensation perceived, and/or by actually measuring NAPs in the tissueof eyes of lab subjects. By triggering NAPs in the various nerve-celllayers 82, 83, and/or 85, certain degeneration effects, defects ordiseases that cause loss of vision can be bypassed by triggering NAPs inthe anterior layers of cells of the retina.

In other embodiments, the IR stimulation light is used to trigger NAPsin the rods or cones, and those NAPs are then combined in the normal wayof processing by the various bipolar, amacrine and/or ganglion layers.

FIG. 8A is a side cross-section view of a stimulation system 801 thatuses a single-depth VCSEL array 887 and a holographic imager 811. Insome embodiments, the stimulation light 130 emitted by the stimulationlight sources (e.g., in some embodiments, an array of independentlyaddressable and separately activatable vertical-cavity surface-emittinglasers (VCSELs) 885 (optionally each including a focussing element 886such as a lens or holograph) implemented on one or more semiconductorchips 887 is of a narrow-linewidth single wavelength laser light. Thissingle wavelength light facilitates focussing using holographs. In someembodiments, a holograph 811 is implemented on the anterior surface 112of ocular unit 801. In some embodiments, holograph 811 facilitatesfocussing the stimulation light at different layers (e.g., variousnerve-cell layers 82, 83, and/or 85 and/or the cone/rod cells ofoptical-cell layer 81) of the retina 97. In some embodiments, all of theVCSELs 85 are implemented at a single depth (as a single plane ofemission at the surface of chip 887). In some embodiments, holograph 811is created by doing a numerical simulation of the light sources at thesurface plane of the VCSEL array chip 887 and a plurality of layers atdifferent depths in the retina, in order that various light sourcepoints can be activated to trigger NAPs at selected layers (e.g., celllayers 81, 82, 83, and/or 85) and selected Cartesian coordinates on theretina 97 (i.e., at the three-dimensional coordinate of the desiredcells to be stimulated).

FIG. 8B is a side cross-section view of a stimulation system 802 thatuses a VCSEL array 888 having a plurality of depths and a holographicimager 812. In some embodiments, the VCSELs 85 are implemented at aplurality of depths (as a plurality of planes of emission at the surfaceof chip 887). In some such embodiments, by having different planes ofemission (by having the emission face of the VCSELs 885 at differentlevels, and/or by having the focussing lenses 886 have different heightsfrom the chip or different focal lengths, or other suitableconfiguration), the ocular unit's focussing element (e.g., lens 116 ofFIG. 1A or holograph 812 of FIG. 8B) can focus the light from thedifferent emission planes onto different layers of cells (e.g., theganglion nerve cells 85, the amacrine nerve cells 83, and/or the bipolarnerve cells 82, and/or the cone/rod cells ofoptical-wavelength-detecting cell layer 81) in the retina 97. In someembodiments, holograph 812 is created by doing a numerical simulation ofthe light sources at the plurality of emission planes of the VCSEL arraychip 887 and a plurality of layers at different depths in the retina, inorder that various light source points can be activated to trigger NAPsat selected layers (e.g., cell layers 81, 82, 83, and/or 85) andselected Cartesian coordinates on the retina 97 (i.e., at thethree-dimensional coordinate of the desired cells to be stimulated).

FIG. 9 is a graph that shows the transmittance of light with wavelengthsof 0.5 microns to 2.5 microns through a typical commercially availableacrylic (PMMA) material. This specific data is from a one-eighth-inch(3.17 mm)-thick piece of an acrylic (PMMA) product available fromFresnel Technologies, Inc. in Fort Worth, Tex. It can be seen that theamount of light transmitted through the PMMA material variesconsiderably with the wavelength of light, from 90 percent or moretransmitted at shorter wavelengths (e.g., less than 1.2-micronwavelengths) to almost none at some longer wavelengths (e.g., greaterthan 2.2-micron wavelengths). Throughout the infrared region of about1000 nm (shown as 1.0 μm on the graph) to 2000 nm (2.0 μm), there aresharp peaks and valleys of transmittance. In some embodiments, a polymermaterial is used that has a relatively high transmittance at thewavelengths used by the present invention (greater than 50% of theincident light is transmitted out the posterior end). In someembodiments, a polymer material (such as PMMA) having a highbiocompatibility is used as an outer layer or coating on the ocularimplant, and a different material (such as glass or another polymer) isused for most of the light-transmission path in the case where thecoating material is not transparent enough at the wavelengths used, orwhere the coating material has a density (mass-per-volume) that isdifferent than what is wanted (e.g., a density that matches the densityof the fluids in the eye).

FIG. 10 is a graph showing the absorption of light with variouswavelengths in a range of 1000 nm to 2100 nm (output intensity as apercent of the input intensity) for a 0.5-mm-thick layer of water. Aswith PMMA, the amount of light transmitted though water variesconsiderably over this range of light wavelengths, with multiple peaksof absorption. The vitreous humor of an eye is 98-99% water, so thisgraph, showing the absorption by water, approximates the absorption ofvarious wavelengths of infrared light in vitreous humor.

Neurons that make up the retina of an eye can be directly stimulated bylight such that NAPs or CNAPs are triggered. The NAP or CNAP response ofthe neurons depends on the energy (power times pulse duration) absorbedper unit area and wavelength (absorption by various tissues varies as afunction of wavelength) of the light pulses impinging on and therebydirectly stimulating the neurons. Neurons are sensitive to wavelengthsof light in the range of about 1800 nm to about 1900 nm. FIG. 9illustrates that PMMA has a relatively high transmittance in most ofthis wavelength range so it is a good choice of material fortransmitting infrared light from an external light source to the retinalnerves of an eye, in some embodiments. However, FIG. 10 shows that water(and thus vitreous humor) has very high light absorption for wavelengthslonger than 1900 nm, and relatively high absorption in much of thewavelength range of between about 1800 nm to about 1900 nm. Thus, someembodiments of the present invention use wavelengths that represent acompromise between wavelengths that are readily absorbed by the nervesto trigger a NAP response, and those that readily pass through the thinlayer of vitreous humor at the posterior end of the ocular implantand/or the thin layer of aqueous humor at the anterior end. Locating therespective ends of the intraocular implant close to the front and rearsurfaces of an eye results in greater light signal transmission from theexternal light to the retinal nerves, but benefits from more preciselymanufactured components and a more complex surgical implant procedureneeded to get a close fit. Conversely, locating the ends of theintraocular implant further from the front and rear surfaces of the eyeresults in the need for less precisely manufactured components andrequires a less complex surgical implant process, and it may bebiologically beneficial to increase the fluid adjacent the tissue, butresults in a decreased amount of signal light transmitted from theexternal light source to the retinal nerves of the eye.

In some embodiments, the light-receiving surface portion of the anteriorend 212 of the ocular unit (according to any of the above-describedembodiments of the present invention) is shaped so as to have asubstantially constant spacing from (i.e., to substantially conform to)the inner surface of the cornea of the eye.

In some embodiments, this light-receiving surface portion of theanterior end of the ocular unit is located at a substantially constantspacing of no more than 2.5 mm from the inner surface of the cornea ofthe eye. In some embodiments, this light-receiving anterior surfaceportion is located at a substantially constant spacing of no more than2.0 mm from the inner surface of the cornea of the eye. In someembodiments, this light-receiving anterior surface portion is located ata substantially constant spacing of no more than 1.5 mm from the innersurface of the cornea of the eye. In some embodiments, thislight-receiving anterior surface portion is located at a substantiallyconstant spacing of no more than 1.0 mm from the inner surface of thecornea of the eye. In some embodiments, this light-receiving anteriorsurface portion is located at a substantially constant spacing of nomore than 0.5 mm from the inner surface of the cornea of the eye. Insome embodiments, this light-receiving anterior surface portion islocated no more than 0.2 mm from the inner surface of the cornea of theeye. In some embodiments, this light-receiving anterior surface portionis located at a substantially constant spacing of about 0.5 mm from theinner surface of the cornea of the eye. In some embodiments, thislight-receiving anterior surface portion is located at a substantiallyconstant spacing of about 0.2 mm from the inner surface of the cornea ofthe eye.

In some embodiments, the light-output surface portion of posterior end214 of the ocular unit (according to any of the above-describedembodiments of the present invention) is shaped so as to have asubstantially constant spacing from (i.e., to substantially conform to)the ganglion layer of the retina of the eye.

In some embodiments, the light-output surface portion of posterior endof the ocular unit is located at a substantially constant spacing of nomore than 2.5 mm from the ganglion layer of the retina of the eye. Insome embodiments, this light-output surface portion is located at asubstantially constant spacing of no more than 2.0 mm from the ganglionlayer of the retina of the eye. In some embodiments, this light-outputsurface portion is located at a substantially constant spacing of nomore than 1.5 mm from the ganglion layer of the retina of the eye. Insome embodiments, this light-output surface portion is located at asubstantially constant spacing of no more than 1.0 mm from the ganglionlayer of the retina of the eye. In some embodiments, this light-outputsurface portion is located at a substantially constant spacing of nomore than 0.5 mm from the ganglion layer of the retina of the eye. Insome embodiments, this light-output surface portion is located at asubstantially constant spacing of no more than 0.2 mm from the ganglionlayer of the retina of the eye. In some embodiments, this light-outputsurface portion is located at a substantially constant spacing of about0.5 mm from the ganglion layer of the retina of the eye. In someembodiments, this light-output surface portion is located at asubstantially constant spacing of about 0.2 mm from the ganglion layerof the retina of the eye.

FIG. 11 is a graph of the raw data used to compute the absorption curvelabeled Kou et al. in FIG. 10. This graph is based on data from Kou, L.,D. Labrie, and P. Chylek, “Refractive indices of water and ice in the0.65-2.5-μm spectral range,” Appl. Opt., 32, 3531-3540, 1993. Othersources provide similar data, for example, Bashkato, A., Genina, E.,Kochubey, E., Kamenskikh, T., and Tuchin, V, “Optical Clearing of HumanEye Sclera,” Proc. Of SPIE, Vol. 7163.

In some embodiments, the present invention provides an apparatus to aidin the treatment of a vision problem of an eye of a person, wherein theeye has an anteroposterior axis extending from the eye's anteriorsurface to the eye's fovea. The apparatus includes an ocular unit havingan optical path 199 that is substantially transparent (i.e.,transmitting at least 50% of incident light) to at least some infraredwavelengths of light between about 1000 nm and about 2000 nm, whereinthe ocular unit has a light-receiving anterior end closest to the eye'santerior surface and extends to a posterior end, wherein the posteriorend is closer to the fovea than to the eye's anterior surface, andwherein the ocular unit has an a secure-placement feature that isconfigured to be secured to an anatomical feature of the eye.

In some embodiments, the ocular unit extends across, and replaces, morethan 90% of the optical path of the eye of the person, in order toprovide an infrared-transparent optical path that is far moretransparent to the wavelengths of the nerve-stimulation wavelengths ofthe optical stimulation signal light 130 than would have been the normalcomponents of the eye.

In some embodiments, the ocular unit transmits out the posterior endmore than 30% of infrared signal light that is incident on the anteriorend and that has wavelengths in a range between about 1800 and about2000 nm. In some embodiments, the ocular unit transmits out theposterior end more than 30% of infrared light that is incident on theanterior end and that has wavelengths in a range between about 1000 andabout 1200 nm. In some embodiments, the ocular unit transmits out theposterior end more than 30% of infrared light that is incident on theanterior end and that has wavelengths in a range between about 1200 andabout 1400 nm. In some embodiments, the ocular unit transmits out theposterior end more than 30% of infrared light that is incident on theanterior end and that has wavelengths in a range between about 1400 andabout 1600 nm. In some embodiments, the ocular unit transmits out theposterior end more than 30% of infrared light that is incident on theanterior end and that has wavelengths in a range between about 1600 andabout 1800 nm. In some embodiments, the ocular unit transmits out theposterior end more than 30% of infrared light that is incident on theanterior end and that has wavelengths in a range between about 2000 andabout 2500 nm. In some embodiments, the ocular unit transmits out theposterior end more than 30% of infrared light that is incident on theanterior end and that has wavelengths in a range between about 2500 andabout 3000 nm. In some embodiments, the ocular unit transmits out theposterior end more than 50% of infrared light that is incident on theanterior end and that has wavelengths in one or more of the above-listedranges.

In some embodiments, the ocular unit transmits out the posterior endmore than 60% of infrared light that is incident on the anterior end andthat has wavelengths in one or more of the wavelength ranges of betweenabout 1000 to about 1200 nm, between about 1200 and about 1400 nm,between about 1400 and about 1600 nm, between about 1600 and about 1800nm, between about 1800 and about 2000 nm, between about 2000 and about2500 nm, and between about 2500 and about 3000 nm. In some embodiments,the ocular unit transmits out the posterior end more than 70% ofinfrared light that is incident on the anterior end and that haswavelengths in one or more of the wavelength ranges of between about1000 to about 1200 nm, between about 1200 and about 1400 nm, betweenabout 1400 and about 1600 nm, between about 1600 and about 1800 nm,between about 1800 and about 2000 nm, between about 2000 and about 2500nm, and between about 2500 and about 3000 nm. In some embodiments, theocular unit transmits out the posterior end more than 80% of infraredlight that is incident on the anterior end and that has wavelengths inone or more of the wavelength ranges of between about 1000 to about 1200nm, between about 1200 and about 1400 nm, between about 1400 and about1600 nm, between about 1600 and about 1800 nm, between about 1800 andabout 2000 nm, between about 2000 and about 2500 nm, and between about2500 and about 3000 nm. In some embodiments, the ocular unit transmitsout the posterior end more than 90% of infrared light that is incidenton the anterior end and that has wavelengths in one or more of thewavelength ranges of between about 1000 to about 1200 nm, between about1200 and about 1400 nm, between about 1400 and about 1600 nm, betweenabout 1600 and about 1800 nm, between about 1800 and about 2000 nm,between about 2000 and about 2500 nm, and between about 2500 and about3000 nm. In some embodiments, the ocular unit transmits out theposterior end more than half of infrared light that is incident on theanterior end and that has wavelengths in two or more of the wavelengthranges of between about 1000 to about 1200 nm, between about 1200 andabout 1400 nm, between about 1400 and about 1600 nm, between about 1600and about 1800 nm, between about 1800 and about 2000 nm, between about2000 and about 2500 nm, and between about 2500 and about 3000 nm.

In some embodiments of the apparatus, the ocular unit includes athermoplastic material. In some embodiments of the apparatus, the ocularunit includes a biocompatible material. In some embodiments of theapparatus, the ocular unit includes a thermoplastic and biocompatiblematerial. In some embodiments, this material transmits to the posteriorend more than half of infrared light having wavelengths between about1800 and about 2000 nm that is incident on the anterior end. In someembodiments, the material is substantially transparent to otherwavelengths in addition to wavelengths between about 1800 and about 2000nm.

In some embodiments of the apparatus, the biocompatible materialincludes poly(methyl methacrylate) (PMMA).

In some embodiments of the apparatus, the ocular unit includes asubstantially cylindrical-shaped material from the anterior end to theposterior end, and wherein the posterior end of the material has adiameter substantially equal to a diameter of the anterior end of thematerial.

In some embodiments of the apparatus, the ocular unit includes asubstantially conical-shaped material from the anterior end to theposterior end, wherein the posterior end of the material has a diameterthat is larger than a diameter of the anterior end of the material.

In some embodiments of the apparatus, the anterior end of the ocularunit is shaped to form a lens to focus the infrared light on nerves ofthe retina.

In some embodiments of the apparatus, at least part of the ocular unitincludes a hollow portion filled with a gas. In some embodiments, thegas is an inert gas having a pressure of less than or equal to about1000 Torr. In some embodiments, the gas pressure is less than or equalto about 760 Torr. In some embodiments, the gas is under a vacuum ofless than about 500 Torr. In some embodiments, at least one end of thehollow portion is shaped to form a lens to focus the infrared light onnerves of the retina.

In some embodiments of the apparatus, the anterior end of the ocularunit extends to through the anterior of the eye replacing at least partof the eye's cornea, and wherein the ocular unit is securely sealed tothe sclera.

In some embodiments of the apparatus, the anterior end of the ocularunit is posterior to the eye's cornea and the ocular unit is securedinternal to the eye.

In some embodiments of the apparatus, the ocular unit has at least oneindicia mark to facilitate detection of the eye's position.

It is to be understood that the above description is intended to beillustrative, and not restrictive. Although numerous characteristics andadvantages of various embodiments as described herein have been setforth in the foregoing description, together with details of thestructure and function of various embodiments, many other embodimentsand changes to details will be apparent to those of skill in the artupon reviewing the above description. The scope of the invention should,therefore, be determined with reference to the appended claims, alongwith the full scope of equivalents to which such claims are entitled. Inthe appended claims, the terms “including” and “in which” are used asthe plain-English equivalents of the respective terms “comprising” and“wherein,” respectively. Moreover, the terms “first,” “second,” and“third,” etc., are used merely as labels, and are not intended to imposenumerical requirements on their objects.

What is claimed is:
 1. A method for treating a vision problem of an eyeof a person, wherein the eye has an anteroposterior axis extending fromthe eye's anterior surface to the eye's retina, the method comprising:forming an optical path inside the person's eye, wherein the opticalpath is substantially transparent to at least some infrared wavelengthsof light between about 1000 nm and about 1900 nm, wherein the opticalpath has a light-receiving anterior end closest to the eye's anteriorsurface and extends to a posterior end of the optical path; securing theoptical path to an anatomical feature of the eye; generating an imagesignal representative of a scene; generating a pulse-control signalrepresenting pulse parameters that are based on the image signal;generating a spatial pattern of pulsed infrared light signals based onthe pulse-control signal; and transmitting the spatial pattern of pulsedinfrared light signals through the optical path, wherein the spatialpattern of pulsed infrared light signals triggers a nerve-actionpotential response in nerves of a retina layer of the eye of the person.2. The method of claim 1, wherein the transmitting of the spatialpattern includes transmitting more than half of infrared light havingwavelengths between about 1800 and about 1900 nm that is incident on theanterior end.
 3. The method of claim 1, wherein the forming of theoptical path includes forming at least a portion of the optical pathwith a biocompatible material that includes poly(methyl methacrylate)(PMMA).
 4. The method of claim 1, wherein the forming of the opticalpath includes forming the optical path in a material havingsubstantially cylindrical-shaped sides from the anterior end to theposterior end, and wherein the posterior end of the material has adiameter substantially equal to a diameter of the anterior end of thematerial.
 5. The method of claim 1, wherein the forming of the opticalpath includes forming the optical path in a material that tapers fromthe anterior end to the posterior end, and wherein the posterior end ofthe material has a diameter that is larger than a diameter of theanterior end of the material.
 6. The method of claim 1, wherein theforming of the optical path includes shaping an anterior end of theoptical path to form a lens, the method further comprising focusing,using the lens, the spatial pattern of pulsed infrared light signals onnerves of the retina.
 7. The method of claim 1, wherein the forming ofthe optical path includes enclosing a hollow portion of the opticalpath.
 8. The method of claim 1, wherein the forming of the optical pathincludes enclosing a hollow portion of the optical path and filling thehollow portion with an inert gas having a pressure of no more than about1000 Torr.
 9. The method of claim 1, wherein the forming of the opticalpath includes enclosing a hollow portion of the optical path, fillingthe hollow portion with a gas, and shaping at least one end of thehollow portion to form a lens, the method further comprising focusing,using the lens, the spatial pattern of pulsed infrared light signals onnerves of the retina.
 10. The method of claim 1, wherein the anteriorend of the ocular path extends through the anterior surface of the eye,replacing at least part of the eye's cornea, and wherein the securing ofthe optical path to the anatomical feature of the eye includes sealingthe optical path securely to the sclera.
 11. The method of claim 1,wherein the anterior end of the ocular path is posterior to the eye'scornea.
 12. The method of claim 1, further comprising providing anindicia mark on the ocular path to facilitate detection of the eye'sposition.
 13. The method of claim 1, wherein the posterior end is withinabout two mm of the retina of the eye.
 14. A method for treating avision problem of an eye of a person, wherein the eye has ananteroposterior axis extending from the eye's anterior surface to theeye's retina, the method comprising: providing an optical device havingan optical path, wherein the optical path is substantially transparentto at least some infrared wavelengths of light between about 1810 nm andabout 1900 nm, wherein the optical path has a light-receiving anteriorend and a light-emitting posterior end; implanting the optical device inthe eye of the person such that the optical path is inside the person'seye and the anterior end is closest to the eye's anterior surface andthe posterior end is closer to the retina than to the eye's anteriorsurface; securing the optical device to an anatomical feature of theeye; generating an image signal representative of a scene; generating apulse-control signal representing pulse parameters that are based on theimage signal; generating a spatial pattern of pulsed infrared lightsignals based on the pulse-control signal; and transmitting the spatialpattern of pulsed infrared light signals through the optical path,wherein the spatial pattern of pulsed infrared light signals triggers anerve-action potential response in nerves of a retina layer of the eyeof the person.
 15. The method of claim 14, wherein the providing of theoptical device includes forming the optical path in a material havingsubstantially cylindrical-shaped sides from the anterior end to theposterior end, and wherein the posterior end of the material has adiameter substantially equal to a diameter of the anterior end of thematerial.
 16. The method of claim 14, wherein the providing of theoptical device includes forming the optical path in a material thattapers from the anterior end to the posterior end, and wherein theposterior end of the material has a diameter that is larger than adiameter of the anterior end of the material.
 17. The method of claim14, wherein the providing of the optical device includes shaping ananterior end of the optical path to form a lens, the method furthercomprising focusing, using the lens, the spatial pattern of pulsedinfrared light signals on nerves of the retina.
 18. The method of claim14, wherein the providing of the optical device includes enclosing ahollow portion of the optical path and filling the hollow portion withan inert gas having a pressure of no more than about 1000 Torr.
 19. Themethod of claim 14, wherein the implanting of the optical deviceincludes locating the anterior end of the optical device such that theanterior end extends through the anterior surface of the eye, replacingat least part of the eye's cornea, and wherein the securing of theoptical device to the anatomical feature of the eye includes sealing theoptical device securely to the sclera.
 20. A method for treating avision problem of an eye of a person, wherein the eye has ananteroposterior axis extending from the eye's anterior surface to theeye's retina, the method comprising: providing an optical device havingan optical path, wherein the optical path is substantially transparentto at least some infrared wavelengths of light between about 1000 nm andabout 1900 nm, wherein the optical path has a light-receiving anteriorend and a light-emitting posterior end; implanting the optical device inthe eye of the person such that the optical path is inside the person'seye and the anterior end is closest to the eye's anterior surface andthe posterior end is closer to the retina than to the eye's anteriorsurface; securing the optical device to an anatomical feature of theeye; generating an image signal representative of a scene; generating apulse-control signal representing pulse parameters that are based on theimage signal; generating a spatial pattern of pulsed infrared lightsignals based on the pulse-control signal; and transmitting the spatialpattern of pulsed infrared light signals through the optical path,wherein the spatial pattern of pulsed infrared light signals triggers anerve-action potential response in nerves of a retina layer of the eyeof the person.